TUBE 813 / QB2/250

GENERAL DESCRIPTION

The 813 / QB2/250 is a five-electrode beam-power transmitting tube of high sensitivity, designed for use as a modulator, amplifier, and oscillator. The anode is capable of dissipating 125 watts. The cathode is a thoriated-tungsten filament. Maximum ratings apply up to a frequency of 30 megacycles. Cooling is obtained by radiation. For continuous commercial service the output for Class C telegraph service is 275 watts. With adequately shielded circuits neutralization is unnecessary.

TECHNICAL SPECIFICATIONS

ELECTRICAL

Min.

Bogey

Max.

Filament Voltage

9.5

10

10.5

volts

Filament Current at Bogey Voltage

4.7

5

5.3

amp

Transconductance

3750 µmhos

Amplification factor

8.5

Interelectrode Capacitances,measured without external shieldingG1 to PlateInput, G1 to Filament, G2 and G3Output, plate to filament, G2 and G3